Aquatic method

ABSTRACT

Isoxazolylimidazclidinones are useful in the control of aquatic vegetation.

This application is a division, of application Ser. No. 334,410, filed12/24/81, U.S. Pat. No. 4,354,030.

BACKGROUND OF THE INVENTION

The use of chemicals in agriculture has become a common practicethroughout the world. Practically all crops that are grown for humanconsumption are grown in the presence of chemicals. Terrestrialherbicides are routinely employed to control unwanted grassy andbroadleaf weeds in desirable food crops such as corn and soybeans.

While there are numerous chemical agents currently available that areeffective as selective terrestrial herbicides, few agents are availablefor controlling the growth of aquatic vegetation in water bodies such aslakes, ponds, streams, rivers and the like. Most herbicides that areeffective terrestrially are not suitable for use in aquaticenvironments. This may be due to the fact that the terrestrialherbicides simply will not control the aquatic vegetation, theterrestrial herbicide is not stable in an aquatic environment, orbecause the toxicity of the terrestrial herbicides render them unfit foruse in water containing animal life.

Lavanish, in U.S. Pat. No. 4,268,679, recently reported a series ofisoxazolylimidazolidinones that are effective as terrestrial herbicidesand are safe for use on corn, soybeans, wheat and the like. We have nowdiscovered that certain isoxazolylimidazolidinones are useful in thecontrol of aquatic vegetation in bodies of water. An object of thisinvention therefore is to provide an aquatic herbicidal method employingisoxazolylimidazolidinones.

SUMMARY OF THE INVENTION

This invention concerns a method for controlling the growth ofvegetation in bodies of water. The invention is more particularlydirected to a method for controlling the growth of aquatic plantscomprising contacting the plants with an aquatic herbicidally effectiveamount of an isoxazolylimidazolidinone defined by the formula ##STR1##wherein: R¹ is C₁ -C₆ alkyl or allyl;

R² is hydrogen, C₁ -C₆ alkyl, allyl, or hydroxy;

R³ is hydroxy or halo;

R⁴ is hydrogen, C₁ -C₆ alkyl, halo, cyano, or nitro;

R⁵ is C₁ -C₆ alkyl, C₂ -C₆ alkenyl, C₂ -C₆ alkynyl, C₃ -C₇ cycloalkyl,C₁ -C₃ alkyl-C₃ -C₇ cycloalkyl, halo-C₁ -C₆ alkyl, --R⁶ --O--R⁷ or --R⁶--S--R⁷,

where R⁶ is C₁ -C₆ alkylene and

R⁷ is C₁ -C₆ alkyl; or R⁵ is ##STR2## wherein: Z is nitro, halo, or R⁷,and n is 0, 1, 2 or

provided that R² is allyl or hydroxy when R¹ is alkyl, R³ is hydroxy,and R⁵ is alkyl, cycloalkyl, alkylcycloalkyl or haloalkyl.

A preferred method of controlling aquatic vegetation employs a compoundof the above formula wherein R² and R³ both are hydroxy.

Another preferred method employs a compound wherein R⁵ is1,1-dimethylethyl.

A further embodiment of this invention is an aquatic formulationcomprising an isoxazolylimidazolidinone of the above formula and anaquatically-acceptable carrier.

This invention also provides a group of new compounds defined by theformula ##STR3## wherein R¹, R⁴ and R⁵ are as defined above.

DETAILED DESCRIPTION OF THE INVENTION

R¹ in the above formula defines allyl or a C₁ -C₆ alkyl group. The term"C₁ -C₆ alkyl" means both straight and branched chains having up to sixcarbon atoms. Typical C₁ -C₆ alkyl groups include methyl, ethyl,isopropyl, n-butyl, 2-methylpentyl, 1,2-dimethylpropyl, and the like.Methyl is preferred for R¹.

The term "halo" as used herein means fluoro, chloro, bromo and iodo.

Typical C₂ -C₆ alkenyl groups include 2-propenyl, 2-butenyl,2-methyl-3-pentenyl, and 5-hexenyl. Common C₂ -C₆ alkynyl groups include3-hexynyl, 2-propynyl, 2-butynyl, 1-methyl-2-butynyl and the like.

The term "C₃ -C₇ cycloalkyl" includes cyclopropyl, cyclobutyl,cyclopentyl and cycloheptyl. "C₁ -C₃ alkyl-C₃ -C₇ -cycloalkyl" means aC₃ -C₇ cycloalkyl group substituted with a C₁ -C₃ alkyl moiety. Examplesinclude 1-ethylcyclohexyl, 1-methylcyclopropyl, and2-isopropylcyclopentyl.

The term "halo-C₁ -C₆ alkyl" means a C₁ -C₆ alkyl group substituted byone or more halo groups. Trifluoromethyl is a preferred haloalkyl group.Other haloalkyl groups are 2-chloroethyl, 3,4-dibromopentyl,2-bromo-3-iodohexyl, and the like.

The terms "--R⁶ --O--R⁷ " and "--R⁶ --S--R⁷ " refer to groups such asmethoxymethyl, 2-ethoxyethyl, 3-isopropylthiopropyl, methylthiomethyl,6-methylthiohexyl and the like.

Most of the compounds employed in the aquatic method of this inventionare disclosed by Lavanish in U.S. Pat. No. 4,268,679. That patent isincorporated herein by reference. As noted therein,isoxazolylimidazolidinones of the above formula wherein R² is other thanhydroxy are prepared by reacting a 3-aminoisoxazole or a5-aminoisoxazole with phosgene to obtain the corresponding isoxazoleisocyanate, reacting the isocyanate with a 2,2-dialkoxyethylamine toprovide a urea intermediate, and then cyclizing the urea. This overallscheme is depicted below. ##STR4## wherein R¹, R⁴ and R⁵ are as definedabove, R² is other than hydroxy, and "alk" is lower alkyl such as methylor ethyl.

Isoxazolylimidazolidinones having the above general formula wherein R²is hydroxy, which are employed in a preferred embodiment of thisinvention, are prepared by reacting a 3-aminoisoxazole or a5-aminoisoxazole with an isocyanate to form an isoxazolylureaderivative, and then reacting the isoxazolylurea with glyoxal to formthe isoxazolyl-4,5-dihydroxyimidazolidinone. This reaction sequence isdepicted by the following scheme; ##STR5##

The isoxazolyl-4,5-dihydroxyimidazolidinones wherein the hydroxy groupsare cis are valuable in the control of aquatic weeds according to thisinvention, and also serve as intermediates in the synthesis of theisoxazolylimidazolidinone acetonides that are provided as a furtherembodiment of the invention. The acetonides can be prepared by reactionof the cis-4,5-dihydroxy imidazolidinones with acetone in the presenceof a dehydrating agent and dilute mineral acid as follows: ##STR6##Typical dehydrating agents that can be employed include copper sulfate,sulfuric acid, perchloric acid, zinc chloride, and phosphorus pentoxide.The reaction generally is carried out in the presence of excessiveacetone to act as reactant and solvent. The reaction usually is completewithin about one to about twenty-four hours when carried out at about20° to about 50° C. The product is isolated and purified by normalprocedures, for example crystallization, chromatography and the like.

Examples of typical classes of isoxazolylimidazolidinones to be employedin the aquatic method of this invention include those listed below:

A. Those of the formula ##STR7## 1. R¹ is allyl and R³ is hydroxy; a. R²is allyl;

1a.1. R⁴ is H and R⁵ is ##STR8## 1a.2. R⁴ is H and R⁵ is --R⁶ --S--R⁷.1a.3. R⁴ is H and R⁵ is --R⁶ --O--R⁷.

1a.4. R⁴ is H and R⁵ is halo-C₁ -C₆ alkyl, preferably trifluoromethyl.

1.a.5. R⁴ is H and R⁵ is C₃ -C₇ cycloalkyl or C₁ -C₃ alkyl-C₃ -C₇cycloalkyl.

1a.6. R⁴ is H and R⁵ is C₁ -C₆ alkyl.

1a.7. R⁴ is H and R⁵ is tert.-butyl.

1a.8. R⁴ is H and R⁵ is C₂ -C₆ alkenyl.

1a.9. R⁴ is H and R⁵ is C₂ -C₆ alkynyl.

b. R² is C₁ -C₆ alkyl.

1b.1. R⁴ is H and R⁵ is ##STR9## 1b.2. R⁴ is H and R⁵ is --R⁶ --S--R⁷.1b.3. R⁴ is H and R⁵ is --R⁶ --O--R⁷.

1b.4. R⁴ is H and R⁵ is halo-C₁ -C₆ alkyl, preferably trifluoromethyl.

1b.5. R⁴ is H and R⁵ is C₃ -C₇ cycloalkyl or C₁ -C₃ alkyl-C₃ -C₇cycloalkyl.

1b.6. R⁴ is H and R⁵ is C₁ -C₆ alkyl.

1b.7. R⁴ is H and R⁵ is tert.-butyl.

1b.8. R⁴ is H and R⁵ is C₂ -C₆ alkenyl.

1b.9. R⁴ is H and R⁵ is C₂ -C₆ alkynyl.

c. R² is hydroxy.

1c.1. R⁴ is H and R⁵ is ##STR10## 1c.2. R⁴ is H and R⁵ is --R⁶ --S--R⁷.1c.3. R⁴ is H and R⁵ is --R⁶ --O--R⁷.

1c.4. R⁴ is H and R⁵ is halo-C₁ -C₆ alkyl, preferably trifluoromethyl.

1c.5. R⁴ is H and R⁵ is C₃ -C₇ cycloalkyl or C₁ -C₃ alkyl-C₃ -C--cycloalkyl.

1c.6. R⁴ is H and R⁵ is C₁ -C₆ alkyl.

1c.7. R⁴ is H and R⁵ is tert.-butyl.

1c.8. R⁴ is H and R⁵ is C₂ -C₆ alkenyl.

1c.9. R⁴ is H and R⁵ is C₂ -C₆ alkynyl.

2. R¹ is C₁ -C₆ alkyl and R³ is hydroxy.

a. R² is allyl;

2a.1. R⁴ is H and R⁵ is ##STR11## 2a.2. R⁴ is H and R⁵ is --R⁶ --S--R⁷.2a.3. R⁴ is H and R⁵ is --R⁶ --O--R⁷.

2a.4. R⁴ is H and R⁵ is halo-C₁ -C₆ alkyl, preferably trifluoromethyl.

2a.5. R⁴ is H and R⁵ is C₃ -C₇ cycloalkyl or C₁ -C₃ alkyl-C₃ -C₇cycloalkyl.

2a.6. R⁴ is H and R⁵ is C₁ -C₆ alkyl.

2a.7. R⁴ is H and R⁵ is tert.-butyl.

2a.8. R⁴ is H and R⁵ is C₂ -C₆ alkenyl.

2a.9. R⁴ is H and R⁵ is C₂ -C₆ alkynyl.

b. R² is C₁ -C₆ alkyl.

2b.1. R⁴ is H and R⁵ is ##STR12## 2b.2. R⁴ is H and R⁵ is C₂ -C₆alkenyl. 2b.3. R⁴ is H and R⁵ is C₂ -C₆ alkynyl.

c. R² is hydroxy.

2c.1. R⁴ is H and R⁵ is ##STR13## 2c.2. R⁴ is H and R⁵ is --R⁶ --S--R⁷.2c.3. R⁴ is H and R⁵ is --R⁶ --O--R⁷.

2c.4. R⁴ is H and R⁵ is halo-C₁ -C₆ alkyl, preferably trifluoromethyl.

2c.5. R⁴ is H and R⁵ is C₃ -C₇ cycloalkyl or C₁ -C₃ alkyl-C₃ -C₇cycloalkyl.

2c.6. R⁴ is H and R⁵ is C₁ -C₆ alkyl.

2c.7. R⁴ is H and R⁵ is tert.-butyl.

2c.8. R⁴ is H and R⁵ is C₂ -C₆ alkenyl.

2c.9. R⁴ is H and R⁵ is C₂ -C₆ alkynyl.

B. The most preferred compounds for use in the present aquatic methodhave the formula: ##STR14## 1. R¹ is allyl and R³ is hydroxy; a. R² isallyl;

1a.1. R⁴ is H and R⁵ is ##STR15## 1a.2. R⁴ is H and R⁵ is --R⁶ --S--R⁷.1a.3. R⁴ is H and R⁵ is --R⁶ --O--R⁷.

1a.4. R⁴ is H and R⁵ is halo-C₁ -C₆ alkyl, preferably trifluoromethyl.

1a.5. R⁴ is H and R⁵ is C₃ -C₇ cycloalkyl or C₁ -C₃ alkyl-C₃ -C₇cycloalkyl.

1a.6. R⁴ is H and R⁵ is C₁ -C₆ alkyl.

1a.7. R⁴ is H and R⁵ is tert.-butyl.

1a.8. R⁴ is H and R⁵ is C₂ -C₆ alkenyl.

1a.9. R⁴ is H and R⁵ is C₂ -C₆ alkynyl.

b. R² is C₁ -C₆ alkyl.

1b.1. R⁴ is H and R⁵ is ##STR16## 1b.2. R⁴ is H and R⁵ is --R⁶ --S--R⁷.1b.3. R⁴ is H and R⁵ is --R⁶ --O--R⁷.

1b.4. R⁴ is H and R⁵ is halo-C₁ -C₆ alkyl, preferably trifluoromethyl.

1b.5. R⁴ is H and R⁵ is C₃ -C₇ cycloalkyl or C₁ -C₃ alkyl-C₃ -C₇cycloalkyl.

1b.6. R⁴ is H and R⁵ is C₁ -C₆ alkyl.

1b.7. R⁴ is H and R⁵ is tert.-butyl.

1b.8. R⁴ is H and R⁵ is C₂ -C₆ alkenyl.

1b.9. R⁴ is H and R⁵ is C₂ -C₆ alkynyl.

c. R² is hydroxy.

1c.1. R⁴ is H and R⁵ is ##STR17## 1c.2. R⁴ is H and R⁵ is --R⁶ --S--R⁷.1c.3. R⁴ is H and R⁵ is --R⁶ --O--R⁷.

1c.4. R⁴ is H and R⁵ is halo-C₁ -C₆ alkyl, preferably trifluoromethyl.

1c.5. R⁴ is H and R⁵ is C₃ -C₇ cycloalkyl or C₁ -C₃ alkyl-C₃ -C₇cycloalkyl.

1c.6. R⁴ is H and R⁵ is C₁ -C₆ alkyl.

1c.7. R⁴ is H and R⁵ is tert.-butyl.

1c.8. R⁴ is H and R⁵ is C₂ -C₆ alkenyl.

1c.9. R⁴ is H and R⁵ is C₂ -C₆ alkynyl.

2. R¹ is C₁ -C₆ alkyl and R³ is hydroxy.

a. R² is allyl;

2a.1. R⁴ is H and R⁵ is ##STR18## 2a.2. R⁴ is H and R⁵ is --R⁶ --S--R⁷.2a.3. R⁴ is H and R⁵ is --R⁶ --O--R⁷.

2a.4. R⁴ is H and R⁵ is halo --C₁ -C₆ alkyl, preferably trifluoromethyl.

2a.5. R⁴ is H and R⁵ is C₃ -C₇ cycloalkyl or C₁ -C₃ alkyl-C₃ -C₇cycloalkyl.

2a.6. R⁴ is H and R⁵ is C₁ -C₆ alkyl.

2a.7. R⁴ is H and R⁵ is tert.-butyl.

2a.8. R⁴ is H and R⁵ is C₂ -C₆ alkenyl.

2a.9. R⁴ is H and R⁵ is C₂ -C₆ alkynyl.

b. R² is C₁ -C₆ alkyl.

2b.1. R⁴ is H and R⁵ is ##STR19## 2b.2. R⁴ is H and R⁵ is C₂ -C₆alkenyl. 2b.3. R⁴ is H and R⁵ is C₂ -C₆ alkynyl.

c. R² is hydroxy.

2c.1. R⁴ is H and R⁵ is ##STR20## 2c.2. R⁴ is H and R⁵ is --R⁶ --S--R⁷.2c.3. R⁴ is H and R⁵ is --R⁶ --O--R⁷.

2c.4. R⁴ is H and R⁵ is halo --C₁ -C₆ alkyl, preferably trifluoromethyl.

2c.5. R⁴ is H and R⁵ is C₃ -C₇ cycloalkyl or C₁ -C₃ alkyl-C₃ -C₇cycloalkyl.

2c.6. R⁴ is H and R⁵ is C₁ -C₆ alkyl.

2c.7. R⁴ is H and R⁵ is tert.-butyl.

2c.8. R⁴ is H and R⁵ is C₂ -C₆ alkenyl.

2c.9. R⁴ is H and R⁵ is C₂ -C₆ alkynyl.

Compounds specifically provided by this invention as new compositions ofmatter are defined by the formula ##STR21## wherein R¹, R⁴ and R⁵ are asdefined above. Exemplary of these new acetonideisoxazolylimidazolidinones are the following:

C. Those of the formula ##STR22## 1. R¹ is allyl. a. R⁴ is hydrogen.

1a.1. R⁵ is ##STR23## 1a.2. R⁵ is --R⁶ --S--R⁷. 1a.3. R⁵ is --R⁶--O--R⁷.

1a.4. R⁵ is halo-C₁ -C₆ alkyl, preferably trifluoromethyl, for example:

3-(5-trifluoromethyl-3-isoxazolyl)-1-allyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

1a.5. R⁵ is C₃ -C₇ cycloalkyl or C₁ -C₃ alkyl-C₃ -C₇ cycloalkyl;

3-(5-cyclohexyl-3-isoxazolyl)-1-allyl-4,5-dihydroxy-2-imidazolidinoneacetonide;

3-[5-(1-ethylcyclohexyl)-3-isoxazolyl]-1-allyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

1a.6. R⁵ is C₁ -C₆ alkyl.

3-(5-isopropyl-3-isoxazolyl)-1-allyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

1a.7. R⁵ is tert.-butyl.

3-(5-tert.-butyl-3-isoxazolyl-1-allyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

1a.8. R⁵ is C₂ -C₆ alkenyl.

1a.9. R⁵ is C₂ -C₆ alkynyl.

2. R¹ is C₁ -C₆ alkyl.

a. R⁴ is hydrogen.

2a.1. R⁵ is ##STR24## 2a.2. R⁵ is --R⁶ --S--R⁷. 2a.3. R⁵ is --R⁶--O--R⁷.

2a.4. R⁵ is halo-C₁ -C₆ alkyl, preferably trifluoromethyl.

3-(5-trifluoromethyl-3-isoxazolyl)-1-methyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

2a.5. R⁵ is C₃ -C₇ cycloalkyl or C₁ -C₃ alkyl-C₃ -C₇ cycloalkyl.

3-(5-cyclopentyl-3-isoxazolyl)-1-ethyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

3-[5-(1-methylcycloheptyl)-3-isoxazolyl]-1-methyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

2a.6. R⁵ is C₁ -C₆ alkyl.

3-(5-isopropyl-3-isoxazolyl)-1-methyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

2a.7. R⁵ is tert.-butyl.

3-(5-tert.-butyl-3-isoxazolyl)-1-methyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

2a.8. R⁵ is C₂ -C₆ alkenyl.

2a.9. R⁵ is C₂ -C₆ alkynyl.

D. Those of the formula ##STR25## 1. R¹ is allyl. a. R⁴ is hydrogen.

1a.1. R⁵ is ##STR26## 1a.2. R⁵ is --R⁶ --S--R⁷.3-(3-methylthiomethyl-5-isoxazolyl)-1-allyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

1a.3. R⁵ is --R⁶ --O--R⁷.

1a.4. R⁵ is halo-C₁ -C₆ alkyl, preferably trifluoromethyl.

3-(3-trifluoromethyl-5-isoxazolyl)-1-allyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

1a.5. R⁵ is C₃ -C₇ cycloalkyl or C₁ -C₃ alkyl-C₃ -C₇ cycloalkyl.

3-(3-cyclopropyl-5-isoxazolyl)-1-allyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

1a.6. R⁵ is C₁ -C₆ alkyl.

3-[3-(1-ethyl-1-methylpropyl)-5-isoxazolyl]-1-allyl-3,4-dihydroxy-2-imidazolidinoneacetonide.

1a.7. R⁵ is tert.-butyl.

3-(3-tert.butyl-5-isoxazolyl)-1-allyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

1a.8. R⁵ is C₂ 14 C₆ alkenyl.

1a.9. R⁵ is C₂ -C₅ alkynyl.

2. R¹ is C₁ -C₆ alkyl.

a. R⁴ is hydrogen.

2a.1. R⁵ is ##STR27## 2a.2. R⁵ is --R⁶ --S--R⁷. 2a.3. R⁵ is --R⁶--O--R⁷.

3-[3-(1,1-dimethylmethoxymethyl)-5-isoxazolyl]-1-methyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

2a.4. R⁵ is halo-C₁ -C₆ alkyl, preferably trifluoromethyl.

3-(3-trifluoromethyl-5-isoxazolyl)-1-methyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

2a.5. R⁵ is C₃ -C₇ cycloalkyl or C₁ -C₃ alkyl-C₃ -C₇ cycloalkyl.

3-[3-(1-ethylcyclohexyl)-5-isoxazolyl]-1-ethyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

2a.6. R⁵ is C₁ -C₆ alkyl.

3-(3-isopropyl-5-isoxazolyl)-1-methyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

2a.7. R⁵ is tert.-butyl.

3-(3-tert.-butyl-5-isoxazolyl)-1-methyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

2a.8. R⁵ is C₂ -C₆ alkenyl.

2a.9. R⁵ is C₂ -C₆ alkynyl.

3-[3-(2-butynyl)-5-isoxazolyl]-1-methyl-4,5-dihydroxy-2-imidazolidinoneacetonide.

The synthesis of compounds defined herein is more fully illustrated bythe following working examples.

EXAMPLE 1

3-[5-(1,1-dimethylethyl)-3-isoxazolyl]-4,5-dihydroxy-1-methyl-2-imidazolidinone

A solution of 14 grams of 40% (v/v) glyoxal/water was diluted with 1.0%aqueous sodium hydroxide to pH 7-8. This glyoxal/water solution was thenadded in one portion to a solution of 3.4 g. of1-[5-(1,1-dimethylethyl)-3-isoxazolyl]-3-methylurea in 120 ml. ofethanol. The reaction mixture was heated to reflux for one hour, and thesolvent was then removed by evaporation to provide 12.0 grams of yellowoil. The oil was dissolved in diethyl ether and heated, and then themixture was filtered to remove a small amount of insoluble material. Thesolvent was removed from the filtrate to afford 11 grams of oil. The oilwas dissolved in dichloromethane and washed with water. Evaporation ofthe organic solvent provided 4.0 grams of a white foam identified as3-[5-(1,1-dimethylethyl)-3-isoxazolyl]-4,5-dihydroxy-1-methyl-2-imidazolidinone.Mass Spectrum M⁺ Theory 255, Found 255.

EXAMPLE 2

3-[5-(1,1-dimethylethyl)-3-isoxazolyl]-4,5-dihydroxy-1-methyl-2-imidazolidinoneacetonide

To a solution of 1.0 gram of3-[5-(1,1-dimethylethyl)-3-isoxazolyl]-4,5-dihydroxy-1-methyl-2-imidazolidinonein 20 ml. of anhydrous acetone were added three drops of 70% perchloricacid. The reaction mixture stood at ambient temperature for sixteenhours, and then was diluted with 100 ml. of water. The white crystallineprecipitate was collected by filtration and recrystallized from diethylether and hexane to afford3-[5-(1,1-dimethylethyl)-3-isoxazolyl]-4,5-dihydroxy-1-methyl-2-imidazolidinoneacetonide. M.P. 157°-159° C. Mass Spectrum M⁺ Theory 295; Found 295.

Analysis calculated for C₁₄ H₂₁ N₃ O₄ Theory: C, 56.94; H, 7.17; N,14.23. Found: C, 56.65; H, 7.43; N, 13.96.

The aquatic method provided by this invention permits the control andelimination of aquatic weeds employing a compound defined herein. Theinvention contemplates the control and elimination of all forms of plantlife that infests ponds, lakes, water ways, water reservoirs, includingwater towers and containers employed in the storage of water for humanconsumption. The invention thus provides a method for controlling algaeand aquatic plant growth including submersed, floating, emergent andditchbank vegetation. Because the compounds are useful in controlaquatic plant life, an important embodiment of this invention is amethod of use employing the compounds.

The novel compounds provided by this invention, with potent aquaticherbicides, also have some terrestrial herbicidal activity. Thepre-emergent and post-emergent terrestrial herbicidal activity oftypical isoxazolylimidazolidinone acetonides of this invention has beendetermined in standard greenhouse experiments. Such experiments werecarried out by first formulating a test compound for convenient soilsurface or overtop foliar spray application. The test compound wasformulated by dissolving 0.2 percent by weight in a solution containing4.0 percent by weight acetone, 4.0 percent by weight ethanol, and 91.7percent by weight of deionized water, and 0.1 percent by weight of acommercial surfactant, for example Toximul R and S, which are blends ofanionic and nonionic surface active agents (Stepan Chemical Co.Northfield, Ill., 60093). The solution containing the test compound wasthen serially diluted with deionized water to the appropriate volumecontaining the desired concentration of test compound. The formulatedcompounds were applied pre-emergence and/or post-emergence to metalgreenhouse flats filled with soil and seeded to test plants. Thecompounds were evaluated at several application rates, initially at 15pounds per acre (16.8 kg/ha) and at lower rates until compound activitydiminished. Pre-emergence applications were made to the soil surface ofthe seeded flats. Post-emergence applications were made to the foliageof the various plant species approximately twelve days after seeding.All treated flats were maintained in a greenhouse following treatment.Evaluations of compound activity were made in the form of plant injuryrating on a scale of 1 to 5. The rating of "1" refers to no plantinjury; "2" slight injury; "3" moderate injury; "4" severe injury; and"5" death to all treated plants. Evaluations were made from 11 to 14days after post-emergence application, and from 18 to 21 days followingpre-emergence application.

Table 1 which follows presents the herbicidal activity of a compoundprovided by this invention.

                  TABLE 1                                                         ______________________________________                                        Plant Injury Ratings for the Compound of Example 2                                        appln. rate lbs/A (kg/ha)                                         PLANT SPECIES 15       8     4      2   1                                     ______________________________________                                        Pre-emergence                                                                 Corn                                                                          Cotton                                                                        Soybean                                                                       Wheat                                                                         Alfalfa                                                                       Sugar Beet                                                                    Rice                                                                          Cucumber                                                                      Tomato        1        1                                                      Barnyard Grass         1                                                      Lambsquarter                                                                  Large Crabgrass                                                                             1        2                                                      Mustard                1                                                      Pigweed       1        4                                                      Foxtail                3                                                      Wildoat                1                                                      Velvetleaf             3                                                      Jimsonweed                                                                    Morningglory           2                                                      Zinnia                 1                                                      Post-emergence                                                                Tomato        3        1     2      1   1                                     Large Crabgrass                                                                             3        2     3      1   1                                     Pigweed       5        5     5      3   2                                     Foxtail                2     3      3   1                                     Velvetleaf             2     4      2   1                                     Morningglory           2     2      2   1                                     Zinnia                 3     2      1   1                                     Wildoat                1     1      1   1                                     ______________________________________                                    

The compounds defined by this invention are particularly useful asaquatic algicides, aquatic growth regulators and aquatic herbicides. Apreferred embodiment of this invention is a method for controllingaquatic plant growth which comprises applying an aquatic herbicidallyeffective amount of a compound as defined herein to the aquatic plantsto be controlled or to the water in which the plants are growing.

The compounds of the invention have been evaluated in a standard aquaticalgicide test designed to show algicidal activity. In a primary screen,the compounds were evaluated against Chlorella vulgaris, Scenedesmusquadricanda, and Anacystis nidulans. These algae species were grown onagar slants containing artificial media (Hughes' media). The agar slantswere employed in the inoculation of the test media, which itself is anaqueous Hughes' media. Five milliliters of sterile Hughes' media is usedto wash the agar slants, and this is then added to 400 ml. of sterileHughes' media. Two milliliters of the inoculated media is then added toeach of several 12 ml. disposable vials.

The test compounds are formulated for evaluation by dissolving 10 mg. ofcompound in a solution of 0.5 ml. acetone and 4.5 ml. of sterile 0.1%aqueous polyoxyethylene sorbitan monooleate (Tween 80). Aliquot portionsof the formulated test compounds are then added to the vials containingthe various algae species. Visual observations and comparisons tonon-treated control vials were made 7 days after treatment. Activityratings were made on a scale of 1 to 5 according to the followingmeanings:

1=no effect

2=slight effect

3=moderate effect

4=heavy effect

5=100% control.

Table 2 which follows presents the algicidal activity of compounds ofthe invention evaluated according to the foregoing procedure.

                  TABLE 2                                                         ______________________________________                                        Aquatic Algicide Activity                                                             Con-                                                                  Compound                                                                              cen-    Control Ratings                                               of Exam-                                                                              tration Chlorella                                                                              Scenedesmus                                                                            Anacystis                                                                            Ana-                                 ple No. ppm     vulgaris quadricanda                                                                            nidulans                                                                             baena                                ______________________________________                                        Control         0        0        0      0                                    2       10      5        5        5      1                                    ______________________________________                                    

As noted above, the compounds of this invention also have activity inthe regulation of aquatic plant growth and are useful as aquaticherbicides. The following method was used in the laboratory to evaluatethe aquatic growth regulating properties of the compounds disclosedherein.

The compounds for this test were formulated in the following manner.Twenty milligrams of compound was weighed into a 12 ml. disposable vial.To the vial containing the compound were added 1 ml. of acetone and 9ml. of aqueous 0.1 percent polyoxyethylene sorbitan monooleate (Tween80). This solution was then diluted with appropriate volumes of water toobtain solutions containing 10, 1, 0.5 and 0.25 ppm (parts per million)of test compound.

Terminal pieces of Florida elodea, Hydrilla verticillata (L.F.),(hereinafter identified as hydrilla) 10 cm. long, without branching,were prepared for testing. Three such cuttings were placed in eachplastic container holding 785 ml. of water containing the formulatedtest compound and 3 ml. of Hoagland's nutrient solution. Three 10 cm.cuttings of hydrilla were placed in each of several control containersof water. To the water in each control container there was also addedthe amount of solvent used to formulate the test compound for eachcontainer.

After a period of two to three weeks, measurements were made todetermine the total length of each plant. An average total growth wasobtained by dividing the total combined lengths by the number ofreplicates. By subtracting 10 cm. from the average total length, theaverage increase in growth was obtained. This difference was divided bythe average increase in length of the plants in the solvent controls(SC) and the quotient multiplied by 100 to give a percent inhibition.##EQU1##

Several of the compounds of the invention were evaluated further asaquatic herbicides by employing additional weed species. The compoundswere formulated for evaluation as described above, and the herbicidalactivity was determined by visual observations based upon non-treatedcontrols. Activity ratings were made on a scale of 1 to 5 as follows:

    ______________________________________                                                1 = no observable effect                                                      2 = slight plant injury                                                       3 = moderate plant injury                                                     4 = 50-90% plant injury                                                       5 = plants completely killed                                          A = abscission   D = stem disintegration                                      C = chlorosis    N = necrosis                                                 ______________________________________                                    

The results of this test are reported in Tables 3 and 4 which follow.

                  TABLE 3                                                         ______________________________________                                        Aquatic Herbicide Activity 3-weeks post-treatment                             Compound of                                                                            Concentration                                                        Example No.                                                                            ppm         Hydrilla Coontail                                                                             Duckweed                                 ______________________________________                                        Control              1        1      1                                        1        10          4D/2D    1/1    5C/5C                                             4           1/2N     1/2C   4C/3C                                             2           1/1      1/2C   1/2C                                     2        4           1/1      1/1    1/1                                               2           2N/2N    2C/1   1/1                                      ______________________________________                                    

                  TABLE 4                                                         ______________________________________                                        Aquatic Herbicide Activity                                                    Compound of Example No.                                                       Control 2                                                                               Concentration ppm                                                                    2      1       0.5                                           ______________________________________                                        1-week post                                                                   treatment                                                                     Hydrilla    1          1        1     1                                       Coontail    1          1        1     1                                       Duckweed    1          2C       1     1                                       S. Naiad    1          3C       1     1                                       Eurasian    1          3C       1     1                                       Milfoil                                                                       Cabomba     1          2C       2C    1                                       Sago Pond   1          1        1     1                                       Weed                                                                          2-week post                                                                   treatment                                                                     Hydrilla    1          1        1     1                                       Coontail    1          3C       2C    2C                                      Duckweed    1          1        1     1                                       S. Naiad    1          3D       3C    1                                       Eurasian    1          2N       1     1                                       Milfoil                                                                       Cabomba     1          2C       3C    1                                       Sago Pond   1          2N       1     4C                                      Weed                                                                          3-week post                                                                   treatment                                                                     Hydrilla    1          1        1     1                                       Coontail    1          3C       3C    3C                                      Duckweed    1          1        1     1                                       S. Naiad    1          3D       1     2D                                      Eurasian    1          3D       1     2C                                      Milfoil                                                                       Cabomba     1          2C       2A    3C                                      Sago Pond   1          2C       1     4C                                      Weed                                                                          ______________________________________                                    

The compounds of the invention are also expected to be useful in thecontrol of water hyacinth. Water hyacinth is a floating aquatic plant ofthe order Eichhornia crassipes of the family Pontederiaceae. The plantis very troublesome in warm regions since it floats on water and oftenclogs waterways, and is very difficult to control safely.

As the data presented in the Tables above demonstrate, the compoundsdefined herein are useful in the control of aquatic vegetative growth. Apreferred embodiment of this invention is a method of eliminating andcontrolling the growth of aquatic plants. This method is practiced byadding the active isoxazolylimidazolidinone derivatives to the watercontaining the submerged, emergent, ditchbank or floating aquaticplants, or otherwise contacting the plants with the active compounds,for example, by applying the compounds to the sub-aqueous soil in whichthe aquatic plants are rooted. The compounds may be applied to the wateras dusts when admixed with a powdered solid carrier such as bentonite,Fuller's earth, diatomaceous earth, or various mineral silicates, e.g.,mica, talc, pyrophyllite, and clays. The compounds may also be mixedwith surface-active dispersing agents to form concentrates to facilitatedispersion in water and to improve the wetting properties when used assprays. If desired, the compounds may be mixed with a powdered solidcarrier, together with a surface-active dispersing agent, so that awettable powder may be obtained which may be applied directly, or whichmay be shaken with water to make an aqueous dispersion for applicationin that form. These wettable powder formulations suitably contain fromabout 25 to about 85 percent by weight of the active ingredient, i.e.,an aquatic growth regulating compound coming within the scope of thegeneric formulae, supra. The compounds may be dissolved in an oil, suchas a hydrocarbon or chlorinated hydrocarbon oil, and the oil solution ofthe compound dispersed in water with the aid of a surface-activedispersing agent to give a sprayable aqueous dispersion. Suchsurface-active dispersing agents may be anionic, nonionic, or cationicsurface-active agents. Such surface-active agents are well-known, andreference is made to Hoffman et al., U.S. Pat. No. 2,614,916, columns2-4, for detailed examples of the same. The compounds useful in thisembodiment of the invention may also be applied by the aerosol method.Solutions for the aerosol treatment may be prepared by dissolving thecompound directly in the aerosol carrier, which is a liquid underpressure, but which is a gas at ordinary temperature (e.g. 20° C.) andatmospheric pressure; or, the aerosol solution may be prepared by firstdissolving the compound in a less volatile solvent, and then admixingsuch solution with the highly volatile liquid aerosol carrier.

Further, the compounds useful as aquatic growth regulators can also beapplied in an invert emulsion formulation. An invert emulsionformulation is prepared by first making a solution of an aquatic growthregulating compound in heavy oils, such as diesel fuel, inverting oil,and the like, and combining the thus-obtained solution with water underhigh shear stirring. The thick emulsion is placed in the water and sinksto the bottom of the lake, river, pond, or the like, and the aquaticgrowth regulator is gradually released to control the growth of theaquatic plants. The following is an example of an invert emulsionformulation, prepared using the compound of Example No. 2 of thisapplication.

    ______________________________________                                        Invert Emulsion                                                               ______________________________________                                        Compound of Example No. 2                                                                             12.5   gm                                             Diesel Fuel             333    ml                                             Inverting oil*          333    ml                                             ______________________________________                                         *Vioko-Rhap Inverting Oil (Rhodia, Inc.)                                 

Two-hundred fifty milliliters of this solution is combined with 3750 ml.of water under high shear stirring to give a thick invert emulsion.

The compounds useful as aquatic growth regulators can also be applied aspellets which are prepared from a mixture of about 5% of the activeingredient, about 85% clay, and about 10% water, all percentages beingby weight. The mixture is then extruded through a pellet mill using asuitably sized die, e.g., about 1/8 in. diameter. The extruded pelletsare about 1/8 in. by 11/2 in., and are then dried to about 8% moisturecontent.

The method of controlling aquatic plant growth provided by thisinvention is practiced by adding to the water containing the submergedor floating plants a growth-regulating or herbicidal amount of one ofthe herein-disclosed compounds, such that a concentration of from about0.01 to about 10 ppm. of the active compound is attained. A preferredmethod of aquatic plant growth regulation provided by this invention isdirected toward the control of plants such as water hyacinth. Suchplants can be controlled by foliar or root application of a compound ofthis invention at a rate of about 0.01 to about 1.0 pounds per acre(about 0.011 to about 1.1 kg/ha).

The optimum concentration of active compound for any specific aquaticweed control problem varies with the temperature, the species to becontrolled, and the shape of the body of water to be treated. At higherwater temperatures, less compound is generally required for a givendegree of control than is needed at lower temperatures. When used tocontrol algae or aquatic plant growth, the compounds will usually beemployed at concentrations of about 0.1 to about 10 ppm. In terms ofpounds of compound per acre of water one foot deep, 0.1 to 10 ppm. isequal to about 0.3 to about 30 pounds per acre of water one foot deep.

We claim:
 1. A method for controlling the growth of aquatic plantscomprising contacting the plants or the water in which the plants aregrowing with an aquatic herbicidally-effective amount of a compound ofthe formula: ##STR28## wherein: R¹ is C₁ -C₆ alkyl or allyl;R² ishydrogen, C₁ -C₆ alkyl, allyl, or hydroxy; R³ is hydroxy or halo; R⁴ ishydrogen, C₁ -C₆ alkyl, halo, cyano, or nitro; R⁵ is C₁ -C₆ alkyl, C₂-C₆ alkenyl, C₂ -C₆ alkynyl, C₃ -C₇ cycloalkyl, C₁ -C₃ alkyl-C₃ -C₇cycloalkyl, halo-C₁ -C₆ alkyl, --R⁶ --O--R⁷ or --R⁶ --S--R⁷, where R⁶ isC₁ -C₆ alkylene and R⁷ is C₁ -C₆ alkyl; or R⁵ is ##STR29## wherein: Z isnitro, halo, or R⁷, and n is 0, 1, 2 or 3; provided that R² is allyl orhydroxy when R¹ is allyl, R³ is hydroxy, and R⁵ is alkyl, cycloalkyl,alkylcycloalkyl or haloalkyl.
 2. The method of claim 1 employing acompound wherein R⁴ is hydrogen.
 3. The method of claim 2 employing acompound wherein R³ is hydroxy.
 4. The method of claim 3 employing acompound wherein R² is hydroxy.
 5. The method of claim 4 employing acompound wherein R¹ is C₁ -C₆ alkyl.
 6. The method of claim 5 employinga compound wherein R¹ is methyl.
 7. The method of claim 6 employing acompound wherein R⁵ is halo-C₁ -C₆ alkyl.
 8. The method of claim 7employing a compound wherein R⁵ is trifluoromethyl.
 9. The method ofclaim 6 employing a compound wherein R⁵ is C₁ -C₆ alkyl.
 10. The methodof claim 9 employing a compound wherein R⁵ is tert.-butyl.
 11. Themethod of claim 10 employing a3-(3-tert.-butyl-5-isoxazolyl)-1-methyl-4,5-dihydroxy-2-imidazolidinone.12. The method of claim 10 employing3-(5-tert.-butyl-3-isoxazolyl)-1-methyl-4,5-dihydroxy-2-imidazolidinone.13. The method of claim 9 employing a compound wherein R⁵ is isopropyl.14. The method of claim 13 employing a3-(5-isopropyl-3-isoxazolyl)-1-methyl-4,5-dihydroxy-2-imidazolidinone.15. The method of claim 13 employing3-(3-isopropyl-5-isoxazolyl)-1-methyl-4,5-dihydroxy-2-imidazolidinone.16. An aquatic formulation comprising an isoxazolylimidazolidinone asdefined in claim 1 together with an aquatically-acceptable carrier. 17.The formulation of claim 16 wherein the active ingredient is a compoundof the formula ##STR30## wherein: R¹ is C₁ -C₆ alkyl or allyl;R⁴ ishydrogen, C₁ -C₆ alkyl, halo, cyano, or nitro; R⁵ is C₁ -C₆ alkyl, C₂-C₆ alkenyl, C₂ -C₆ alkynyl, C₃ -C₇ cycloalkyl, C₁ -C₃ alkyl-C₃ -C₇cycloalkyl, halo-C₁ -C₆ alkyl, --R⁶ --O--R⁷ or --R⁶ --S--R⁷, where R⁶ isC₁ -C₆ alkylene and R⁷ is C₁ -C₆ alkyl; or R⁵ is ##STR31## wherein: Z isnitro, halo, or R⁷, and n is 0, 1, 2 or
 3. 18. The formulation of claim17 wherein R¹ is alkyl.
 19. The formulation of claim 18 wherein R⁴ ishydrogen.
 20. The formulation of claim 19 wherein R⁵ is C₁ -C₆ alkyl.21. The formulation of claim 20 wherein R⁵ is tert.-butyl.
 22. Theformulation of claim 20 wherein R⁵ is iso-propyl.
 23. The formulation ofclaim 19 wherein R⁵ is halo-C₁ -C₆ alkyl.
 24. The formulation of claim23 wherein R⁵ is trifluoromethyl.